Tracking: release 1.0 and adopt semver

[cschleiden]

At some point I want to release a version 1.0 of this library and start following semver for breaking changes. This issue tracks the work I think is necessary for that.

Tasks

Beta Give feedback

1. Support database migrations #244
   backend:mysql backend:sqlite feature +3
2. panic: runtime error: index out of range [-1] when retrieving workflow task #200
   bug +1
3. Breakout docs into separate page #263
   docs +1
   
4. Don't panic #280
   1 of 1
   +0
   
5. Prevent creating multiple workflow instances with the same instance id #260
   +0
6. Improve tracing #335
   enhancement metrics +2
7. Remove workflow instance data immediately when using ContinueAsNew #315
   backend:mysql backend:sqlite enhancement +3
   
8. Clean up data for finished workflows #28
   backend:mysql backend:sqlite feature +3
   
9. Support different queues for workflows and activities #349
   enhancement +1
   

[cschleiden]

Added the latest batch of bugs and partially implemented features I'd like to fix and finish before releasing 1.0.

[decibelcooper]

@cschleiden Are there any tasks you would like help with to drive this project to v1?

[cschleiden]

@decibelcooper for now I've only got a couple more features planned for 1.0. I bet there are some bugs that need to be fixed, but I got it with the current plan.

[cspotcode]

Is 1.0 going to be the next version, or are you planning other pre-1.0 releases? I ask because I'm hoping to use the new "queue" feature for our side-by-side deploys, so I'm trying to estimate a realistic schedule for that. If I shouldn't expect a stable release in the near-term, then I can use side-by-side backends as a stop-gap.